Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
Inorg Chem. 2014 Jan 6;53(1):167-81. doi: 10.1021/ic4019585. Epub 2013 Dec 20.
A new, DMF-coordinated, preorganized diiron compound Fe2(N-Et-HPTB)(DMF)43 (1) was synthesized, avoiding the formation of Fe(N-Et-HPTB)2 (10) and Fe2(N-Et-HPTB)(μ-MeCONH)2 (11), where N-Et-HPTB is the anion of N,N,N',N'-tetrakis[2-(1-ethylbenzimidazolyl)]-2-hydroxy-1,3-diaminopropane. Compound 1 is a versatile reactant from which nine new compounds have been generated. Transformations include solvent exchange to yield Fe2(N-Et-HPTB)(MeCN)43 (2), substitution to afford Fe2(N-Et-HPTB)(μ-RCOO)2 (3, R = Ph; 4, RCOO = 4-methyl-2,6-diphenyl benzoate]), one-electron oxidation by (Cp2Fe)(BF4) to yield a Robin-Day class II mixed-valent diiron(II,III) compound, Fe2(N-Et-HPTB)(μ-PhCOO)(DMF)23 (5), two-electron oxidation with tris(4-bromophenyl)aminium hexachloroantimonate to generate Fe2(N-Et-HPTB)Cl3(DMF)2 (6), reaction with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl to form Fe5(N-Et-HPTB)2(μ-OH)4(μ-O)(DMF)24 (7), and reaction with dioxygen to yield an unstable peroxo compound that decomposes at room temperature to generate Fe4(N-Et-HPTB)2(μ-O)3(H2O)2·8DMF (8) and Fe4(N-Et-HPTB)2(μ-O)42 (9). Compound 5 loses its bridging benzoate ligand upon further oxidation to form Fe2(N-Et-HPTB)(OH)2(DMF)23 (12). Reaction of the diiron(II,III) compound 5 with dioxygen was studied in detail by spectroscopic methods. All compounds (1-12) were characterized by single-crystal X-ray structure determinations. Selected compounds and reaction intermediates were further examined by a combination of elemental analysis, electronic absorption spectroscopy, Mössbauer spectroscopy, EPR spectroscopy, resonance Raman spectroscopy, and cyclic voltammetry.
一种新的、DMF 配位的、预组织的二铁配合物Fe2(N-Et-HPTB)(DMF)43(1)被合成出来，避免了Fe(N-Et-HPTB)2(10)和Fe2(N-Et-HPTB)(μ-MeCONH)2(11)的形成，其中 N-Et-HPTB 是 N,N,N',N'-四[2-(1-乙基苯并咪唑基)]-2-羟基-1,3-二氨基丙烷的阴离子。化合物 1 是一种多功能的反应物，从中生成了九种新的化合物。转化包括溶剂交换生成Fe2(N-Et-HPTB)(MeCN)43(2)，取代生成Fe2(N-Et-HPTB)(μ-RCOO)2(3,R=Ph;4,RCOO=4-甲基-2,6-二苯基苯甲酸])，用(Cp2Fe)(BF4)单电子氧化生成罗宾-戴 class II 混合价二铁(II,III)化合物Fe2(N-Et-HPTB)(μ-PhCOO)(DMF)23(5)，用三(4-溴苯基)氨基六氯锑酸盐双电子氧化生成Fe2(N-Et-HPTB)Cl3(DMF)2(6)，与(2,2,6,6-四甲基哌啶-1-基)氧反应生成Fe5(N-Et-HPTB)2(μ-OH)4(μ-O)(DMF)24(7)，与氧气反应生成不稳定的过氧化合物，该化合物在室温下分解生成Fe4(N-Et-HPTB)2(μ-O)3(H2O)2·8DMF(8)和Fe4(N-Et-HPTB)2(μ-O)42(9)。化合物 5 进一步氧化失去其桥连苯甲酸配体，生成Fe2(N-Et-HPTB)(OH)2(DMF)23(12)。通过光谱方法详细研究了二铁(II,III)化合物 5 与氧气的反应。所有化合物(1-12)都通过单晶 X 射线结构测定进行了表征。选择的化合物和反应中间体进一步通过元素分析、电子吸收光谱、穆斯堡尔光谱、电子顺磁共振光谱、共振拉曼光谱和循环伏安法进行了检查。
